The present invention relates generally to an improved method and apparatus for producing sealing members for screws, nails and similar fastener devices and it relates more particularly to an improved method and machine for producing tubular sealing members having rolled ends.
In U.S. Pat. No. 3,299,766 granted Jan. 24, 1967 to W. Gould, et al., there are disclosed various forms of sealing elements for fastener devices such as screws, bolts, nails and the like. These sealing elements are formed of a thermoplastic synthetic organic polymeric resin which is relatively stiff and deformable and possesses cold-flow properties and sealing elements of the subject type which are employed to great advantage as those illustrated in FIGS. 7, 8, and 12 of the above identified patent. The preferred form of sealing element includes a sleeve of a resin of the above nature having a rolled over rearwardly turned upper flange or washer portion. However, the preferred form of the sealing element possesses an important drawback in that it has heretofore been difficult to mass produce with great accuracy and is accordingly expensive and of non-uniform quality.